This invention relates generally to microdisplays for displaying information in association with processor-based systems.
A microdisplay is a relatively small display which can be viewed directly, as in a head mounted display, or enlarged by using projection systems, for example. Commonly, microdisplays are less than four centimeters measured diagonally.
Digital microdisplays may contain integrated frame buffers that hold the pixel data for the image being displayed. In order to get a high quality image, a large number of pixels may be utilized. Displaying a large number of pixels requires a relatively large frame buffer to store the data being displayed. The yield of an integrated circuit, which includes both the pixel array and the frame buffer, may be limited by the yield of memory that implements the frame buffer.
Thus, the memory may contain a redundancy repair mechanism to allow the microdisplay to tolerate a certain number of failures during fabrication of the frame buffer. Generally, if bad locations are formed in the frame buffer, the entire frame buffer need not be disposed of because redundant memory blocks may be utilized to replace blocks that have damaged memory location.
Traditional redundancy repair schemes add additional redundant memory to the array that can be swapped in place of the failing elements. Since the overall physical organization of the memory is not relevant to its operation in traditional memories, there are no problems inserting redundant blocks or structures.
However, in a microdisplay, the memory may be tightly coupled to the pixel array that forms the display. In such microdisplays, the physical layout of the bits is constrained by the size and location of the pixels. That is, the memory for a pixel at some location may be adjacent to the memory for a pixel at another location.
Thus, there is a need to enable repair of defective frame buffers in microdisplays.